Variable controls for engine speeds



Feb. 23, 1960 R. C. HElDNER VARIABLE CONTROLS FOR ENGINE SPEEDS Filed Dec. 9, 1955 INVENTOR. RICH/4RD C fla /m? QAQ/M ATTORNEY VARIABLE CONTROLS FOR ENGINE SPEEDS Richard C. Heidner, Hartford, Wis., assignor to West Bend Aluminum (30., West Bend, Wis., a corporation of Wisconsin Application December 9, 1955, Serial No. 552,098

1 Claim. (Cl. 74-517) This invention relates to improvements in speed controls for engines, particularly to such controls which have a variable ratio of motion transmission between a manually movable part and the final control part.

It is an object of this invention to provide a quick retard from high speed and thus create a safer control particularly advantageous when applied to engines used in outboard motors or other applications where rapid deceleration is advantageous.

Another object of this invention is to provide a control which has an easier and finer adjustment in the lower speed ranges such as idling speed. This also is advantageous when applied to engines used in outboard motors where a close control of trolling speed is desirable.

These objects are obtained by moving an adjustable stator plate of a magneto and a throttle control plate by a cam with a spiral path which has radii from its center of rotation which increase from one end to the other end of such path. The short radii portion of such path is used in transferring motion from a hand control to the magneto and throttle control in the high speed ranges. The long radii portion of such path is used to transmit such motion in the low speed ranges. Hence in the high speed ranges only little movement of the control handle is needed to efiectuate the same degree magneto and throttle control as is obtained by a much larger movement of the control handle in the low speed ranges. This provides quick deceleration from high speeds and finer adjustment in low speeds.

One application of an embodiment of this invention is set forth in the following description and shown in the accompanying drawing, in which:

Fig. 1 is a view in side elevation of a speed control embodying this invention as applied to an outboard motor schematically shown in broken lines;

Fig. 2 is an enlarged top plan view of such speed control; and

Fig. 3 is a view in side elevation of such speed control shown in Fig. 2.

Referring to the drawing by reference numerals, the speed control is applied to an outboard motor having an engine with a fiy-wheel 11 and a speed control handle 12 positioned at the end of the steering handle.

As is customary in outboard motor construction, the rotation of the handle 12 is transmitted through suitable gearing shafts to rotate a pulley 14. This pulley is connected by an endless flexible cable 16 to a pulley 18 mounted on a shaft 20 in substantial planar alinement with a stator plate mounted below the fly-wheel 11. A pulley 22 fixed to the shaft 20 provides operative power for a flexible cable 24 which has a rcarwardly projecting end 26 secured to the high speed end of a cam 36 and a forwardly projecting end 28 secured to the low speed end of such cam. The cable 24 passes around a take-up pulley 30 located as shown to guide such cable in reciprocal movement. The pulley 30 is mounted on a pivoted arm 32 urged in a counter-clockwise direction as viewed in Fig. 3 by a spring 34. This provides the necessary driving friction and takes up the slack which occurs in the cable 24 during the operation of the cam.

The cam 36 (part of which also acts as a throttle control plate) is secured to the adjustable stator plate of the magneto for the engine and rotates'about the axis 38 of the engine crankshaft. The cam 36 has a spiral path 40 which provides a guide and track for the cable 24 as it is moved back and forth under control of the handle 12. This spiral path has radii which gradually increase from the length indicated at A to the length indicated at B. In Fig. 2 the cam 36 is shown in full lines at the upper extreme of the high speed range and in the broken lines at the lower extreme of the low speed range. When the handle 12 is first rotated toward slow speed, the lineal movement per unit of the upper run of cable 24 (toward the left) will produce the maximum angular movement for such lineal unit of the cam 36. As such movement of the handle 12 is continued the lineal movement of the cable for such unit will produce less angular movement of the cam 36 until the ratio is at a minimum at the slow speed end after approximately travel.

The length of the path 40 on cam 36 is proportioned to the length of the radii A and B so that upon full movement of the handle 12 within its allowed limits the cam 36 will rotate substantially 90. The movement of the control handle 12 from full speed for approximately one quarter of its total movement will cause the cam 36 to move considerably over one quarter of its full movement thus effecting a quick deceleration. This means that less movement is required on the handle 12 to swing the control from the high speed position of Fig. 2 to an intermediate speed position than is required on presently used controls and constitutes a safety factor in the operation of outboard motors. When the handle 12 is rotated within its range for the low speed, less movement of cam 36 is produced than is now standard. Hence a greater handle movement is required to effect a smaller change in speed and a finer adjustment is thus obtained.

I claim:

In a speed control for an outboard motor having a rotatable part for effecting changes of speed upon rotation thereof, a cam attached to said part having a continuous curved path with radii to center of rotation of such part increasing from a first end to a second end of said path, said path having means providing a guide for a flexible cable, a manually operated drive pulley revolvably mounted in substantial planar alinement with said path and spaced from one side thereof, a take-up pulley revolvably mounted in substantial planar alinement with said drive pulley and said path and spaced from said path on the side opposite to said drive pulley, means for mounting said take-up for movement toward and away from said path, resilient means urging said take-up pulley away from said path, and a flexible cable having one end fixedly secured to the first end of said path, said cable passing along said guide toward said second end of said path around said take-up pulley thence around said drive pulley and back to said guide, the other end of said cable being fixedly secured to the second end of said path.

References Cited in the file of this patent UNITED STATES PATENTS 867,849 Stoker Oct. 8, 1907 2,287,704 Oberg June 23, 1942 2,312,274 Stortz Feb. 23, 1943 2,409,231 Waite Oct. 15, 1946 2,504,286 Wahlberg et al Apr. 18, 1950 

